fossilisation vs fossilise

fossilisation is a noun but fossilise is not a noun.

Word	Noun	Adjective	Verb	Adverb
fossilisation	Yes	No	No	No
fossilise	No	No	Yes	No

fossilisation (noun)	fossilise (noun)
becoming inflexible or out of date
the process of fossilizing a plant or animal that existed in some earlier age; the process of being turned to stone

fossilisation (verb)	fossilise (verb)
	convert to a fossil
	become mentally inflexible